How to nail gable end truss to top plate?

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  #1  
Old 03-30-06, 03:29 PM
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Question How to nail gable end truss to top plate?

I'm erecting the scissor trusses on my house, but I couldn't find anywhere in the literature as to how to properly secure the gable end trusses to the top plate. The gable end scissor trusses are bearing directly on a balloon-framed gable end wall that extends up to the sole of the scissor truss to make a stronger diaphragm.

The truss plans specify uplift and shear requirements at certain points, but not *how* to meet those requirements. The uplift is straightforward- 240lbs at 6 specific points is easy to strap. But the shear is not so straightforward, and straps won't help much. I've been toenailing 8D nails every 6" inside and out along the truss into the top-plate, but it's awkward nailing and they're not going in well, so I switched to 10D nails every 6" to make sure they bite good into the top plate. It really seems like overkill, but if I have a max 50plf shear, I'd need 2 toenailed 8D per foot to cover that, right? I put Xed toenails every 6" because... well... I have no idea why I put every 6", it seems kinda stupid in retrospect. But I certainly don't want my roof to blow off when a hurricane hits!

I also put in 10D sideways into the nailer plate every 16" OC, not that it will do much good, but I figured I might as well.

Thanks
 
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  #2  
Old 03-31-06, 05:43 AM
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Originally Posted by grover
I'm erecting the scissor trusses on my house, but I couldn't find anywhere in the literature as to how to properly secure the gable end trusses to the top plate.
They don't have a website or an phone #?

Why would you not find out the right way to secure the truss BEFORE you did what you have described with YOUR nailing pattern? What if the way you nailed it is wrong?
 
  #3  
Old 03-31-06, 07:45 PM
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The truss drawing says to strap for uplift at 6 specific points which I've done, and to pin the ends to handle 134lbs shear, which I've done. But this still leaves the entire length of the truss pretty much just flapping with any shear load which I know is wrong.

It's not rocket sciense, it's 2x4 joinery with fairly low loads and I've put in enough nails to cover over twice the load that it will see in max 110mph winds. Worst-case, I wait 6 months until I get my PE license and stamp it myself. But I'd rather not have to do that. I was really hoping to find some sort of standard practice before I bust my ass on a 24' extension ladder again tomorrow putting on twice as many nails as I really need to. Is there a standard practice? Should I just treat this truss like I would a roof joist, since the loads are practically identical?

The truss manufacturer's website is useless, and their employees (liability-paranoid, I'm sure) refuse to give out any installation instructions beyond what is stamped by their engineer, who is inconveniently located in a different state and sends in stamped drawings by mail. I haven't tried directly contacting the engineer because I don't have any contact info for him, just his signature and a photocopy of his stamp.
 

Last edited by grover; 03-31-06 at 08:04 PM.
  #4  
Old 04-05-06, 08:38 AM
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this may help

The WTCA (Wood Truss council of america) may have the info you need. Its at least worth looking at their site
 
  #5  
Old 04-07-06, 04:08 AM
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I'm not really sure where to start here, except to tell you hw I would do it. I first of all would never use anything less then a 16D nail for any joists. I would have shot them in with my air nailer about every 6" along the truss into the top sill. Then I would have put on my exterior sheeting, beginning at the bottom of the sill and going up and nailing it onto the outside of the truss and the wall at the same time. This gives double strength. I only use #8's for sheeting, and have never used #10 nails. No strength value. I would forget all the blah, blah , blah about engineering. I am an engineer, and I find common sense alot better then book learning. No truss manufacture will tell you haow to secure them, because they do not know what they are going on. Good Luck Get on you ladder and supplement with some real nails.
 
  #6  
Old 04-07-06, 09:03 AM
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[QUOTE= I only use #8's for sheeting, and have never used #10 nails. No strength value. [/QUOTE]

Jack,

There's no strength value in 10d nails?

Every house or addition I've framed in the past 20 years I've never used anything bigger than a 10d nail. We use 8d's for all studs and sheathing and 10d's for the rest of the house. There's houses built every day with 10d's and they're all still standing.
 
  #7  
Old 04-07-06, 06:27 PM
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Joe:
I know you use 10's and 8's. Lots of Contractors do. And yes, they will stand up for 20 years. But not my company. I use 16's for frameing. Now this is directly from the Builders Bible and I quote "The nail length to use = 3 times the thickness of the material being secured." Now when I am nailing any thing with a 2 x dimension, I use #16 common. They are between 3 1/2 and 4 inches depending on the brand.
 
  #8  
Old 04-08-06, 08:01 AM
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Originally Posted by Jack the Contractor
Joe:
I know you use 10's and 8's. Lots of Contractors do. And yes, they will stand up for 20 years. But not my company. I use 16's for frameing. Now this is directly from the Builders Bible and I quote "The nail length to use = 3 times the thickness of the material being secured." Now when I am nailing any thing with a 2 x dimension, I use #16 common. They are between 3 1/2 and 4 inches depending on the brand.
Jack,


In one of your posts, you said, "There's no strength value in 10d nails?"

That's not true at all. Where did you get that information from?

Are you saying that a house nailed with 16d nails will hold up longer than a house nailed with 10d's?

Never heard of a Builders Bible before but you said that the nail length to use is three times the thickness of the material being secured.

That means you should be using a 4-1/2" nail when nailing 2 x materials which measures 1-1/2". So your 3-1/2 - 4" nail is too small.
 
  #9  
Old 04-08-06, 08:25 AM
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Joe
I am not going to argue with you about using #10 nails to frame with. Code says 16. If you want to use 10 thats ok. I will not nor will I never use them. Strength value too low for me. If you don't believe me ask Doug. He designs homes. My homes are designed for 100 years and winds of at least 150 mph. I was just watching the tornado damage in Tenn. I did not see any of mine knocked down. but I saw alot of other contractors homes destroyed. Have a good day. Oh one thing I forgot. With the new lumber dimensions the nail length would be 3 3/4 length. As I said #16's are between 3 1/2 to 4' depending on the brand. I use whatever brand I can buy at the time.
 
  #10  
Old 04-08-06, 09:39 AM
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Originally Posted by Jack the Contractor
Joe
I am not going to argue with you about using #10 nails to frame with. Code says 16. If you want to use 10 thats ok. I will not nor will I never use them. Strength value too low for me. If you don't believe me ask Doug. He designs homes. My homes are designed for 100 years and winds of at least 150 mph. I was just watching the tornado damage in Tenn. I did not see any of mine knocked down. but I saw alot of other contractors homes destroyed. Have a good day. Oh one thing I forgot. With the new lumber dimensions the nail length would be 3 3/4 length. As I said #16's are between 3 1/2 to 4' depending on the brand. I use whatever brand I can buy at the time.
Jack,

What's to argue about? You’re the one that posted that 10d's has no strength value and it's an open forum and in my 22 years of framing I've never once built a house with anything bigger than 10d's.

It's obviously a regional difference because you said its code where you’re from. You make a statement like that and nothing to back it up and gave no proof as to the strength value being to low.

So, whoever reads this forum has to go by what's code. Also the people reading this forum will know that you CAN frame houses with 10d nails in ceratin areas.

Your right, I don't believe you for the reasons I said above because I've never used 16d nails, so obviously our houses can be built without them. Who is Doug and what difference does it make what he has to say just because he designs homes. Every house or addition that I've built was designed by Architects and Engineers using 10d nails. So, unless Doug is from my area it doesn't make a difference what he says.

You said, “Oh one thing I forgot. With the new lumber dimensions the nail length would be 3 3/4 length. As I said #16's are between 3 1/2 to 4' depending on the brand.”

So what you’re saying is that all your 2x material is 1-1/4”? If that’s the case than your right about the 3-3/4”. But since it’s new, what size nails were you using when the 2x material was 1-1/2” because that’s 4-1/2”?
 
  #11  
Old 04-08-06, 09:52 AM
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Joe - Does your area recognize and enforce the UBC?
 
  #12  
Old 04-08-06, 01:40 PM
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Who Am I?

Joe,

If you want to know who I am, look at my profile. If you want to know who I am here on the Forum, look at my Title.

As Wayne asked - you do not or where you build, doesn't recognize UBC or the more current one, IRC 2003 (International Residential Codes) which will become the standard nationwide. Other older codes will be phased out within each community over time. I realize that we have some areas of the nation that don't enforce or get critical on inspections or even require permits, thus anyone who thinks they are a contractor, does whatever they want. Based on your reply, I am assuming the latter, IMHO.

For those reason(s) you don't seem to have the knowledge as others as to what is considered approved and acceptable methods of construction, IMHO. Those of us that do know and follow Codes, can clearly look in our Code books and readily see what is allowed and is not. This Forum will respond with answers based on current Codes as the IRC or equivelant.

An example:

Table R602.3 (1)

Rafter to Plate, Toe Nail - 2-16D Nails

Pretty much answers grover's question - simple enough!

I suggest that you not argue, which you are. We do have Forum policies and they will be enforced.

Kindly keep in mind that those of us that are Moderators or Super Moderators have some outstanding experience. I also want to point out that we have members that are also just as experienced, if not more qualified, in certain areas than we are. At least we are good enough to admit that and understand that there are those with less knowledge but are willing to help, not hinder a posting when assisting others.

It's not just the years at doing something but understanding what you are doing that give credibility to ones own experience.

As I have always said, length of time doing something doesn't make you have experience. It's a question of, what have you learned during that time to give you that experience.

I can only suggest to discontinue this petty squabble on nail size or strength and look in the Code books. It will answer all your debatable issues, which we obviously cannot satisfy your persistence to disclaim a statement or lack of knowledge on the issues. We need to stay in context to the posters questions, plain and simple.

I consider this posting has been answered in full. If you have a problem with any of this or me, send me a PM, it should not be discussed here in a Public Forum.

Hope this helps!
 
  #13  
Old 04-08-06, 07:36 PM
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I'm in Chesapeake VA, code here is IBC/IRC 2003. Which says 2x 16D for framing, or 4x8D toenailed. 10D are only really for sistering studs/plates and corners. It's Table R602.3(1) if anyone wants to pull our their copy for reference... mine just falls open to that page anymore, as much as I've been referring to it the past few months. I've been using nailgun 8Ds in sheathing, though.


I looked through the wood truss council website for over an hour and still wasn't able to find explitely what I was looking for. They had a brocure on using toenails vice hurricane clips, and gave some numbers on the max uplift that method could tolerate. Nothing mentioned on any of their documents about shear forces on gable end trusses, though... My wind loading is 110mph, which isn't all that strong- a little more than I'd want to toenail, though!

I saw a table recently that listed the shear and pullout stresses for common nails, I'll try to find it. Toenailing only counted as 1/2 of straight nailing.
Edit: big table here: http://www.icc-es.org/reports/pdf_files/UBC/2843.pdf
 
  #14  
Old 04-08-06, 07:44 PM
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Doug - In my area the local inspector uses the UBC. I had coffee with him this afternoon and we discussed this a bit. His position is that while he agreed that maybe 4, 10d nails would do the same job as the 2, 16d nails required by the UBC, there has to be a standard otherwise people would just put stuff together based on what they felt was adequate for the job. With that said, he agreed that nailing schedules should be expanded to include newer nailing configurations.
Codes aside, I don't know how builders can get away with 10d for primary framing when most manufacturers of engineered materials (specifically I joists) require that they be nailed with 16d nails.
 
  #15  
Old 04-08-06, 07:56 PM
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Wayne,

I totally agree! I design and draft all types of projects less commercial. With my background, I have seen bizarre things that so-called contractors do and it just amazes me at what they don't know. I have no choice in what I do for a living. I must do what is right and recommended, either by manufacturer or by the Code (even though Code is the MINIMUM requirements).

Grover, I am unsure why you posted your question if you have a Code book - you referenced the same thing I did. The key issue is that your wall sheathing, if you do it like I do, would tie into your main wall. I do this on any gable end truss. I prefer to overlap my wall sheathing to provide the security that you mentioned. I do realize that many may not balloon frame the gable end walls using a scissor truss but even when they don't, the wall sheathing sure takes care of any uplifting issues when you can't use metal ties. This will act like a hurricane tie or strapping but in places like Florida or California, other stipulations would apply to their use. I admit that I do not have experience in those states due to requirements I'm unfamiliar with.

Hope this helps!
 
  #16  
Old 04-09-06, 07:13 AM
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Doug, the reason I was posting this question is because IRC and the truss mfg specs were silent on this issue. I balloon-framed my wall to the base of the scissor gable end truss and am sheathing to cover the uplift; per a whitepaper I scratched up off engprotips, sheathing can be used in both shear and uplift modes providing uplift is less than 1135 lbs (IIRC) and the nails required for uplift and shear are counted separately- EG, for every 50lbs of uplift required, stick in an extra 8D.

This, however, only handles uplift and not shear. Per IBC, there will be -20psf wind load at the corners, and -16.8psf wind load everywhere else. As 50% of the wind load of the wall diaphragm will be transferred to the gable truss, that's a significant amount of shear! Positive pressure will push the gable against the nailer and drywall, but negative pressure will only have the nails and sheathing to stop it... So I was concerned enough to post here. I'm presently nailing 2x 10D per foot and 2x8D per foot. The way I balloon framed, I only have a single top plate, so I nailed a few 10D through the bottom of the top-plate into the truss, but it was a very awkward nailing angle, so I didn't do this everywhere, only at the peak.

I wonder if most construction workers stop to think of the 500lb reactions when they drive 2 10D nailgun sinkers into the base of a 20' tall balloon-framed 2x4 stud? They certainly wouldn't nail that board like that horizontally across a 20' span and then trust their life to stand on it, why would they trust the house to stand up under hurricane-force winds? I know my foundation contractor was laughing at the number of anchor bolts I insisted on using, but by the numbers for wind shear, they're actually only marginally overengineered. If standard practice is only 1/3 of what I used, I'd hate to think of what will happen to those houses if a strong cat 3 hits this area...
 

Last edited by grover; 04-09-06 at 07:23 AM.
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